Cortical Auditory Evoked Potential Indices of Impaired Sensory Gating in People With Chronic Tinnitus.

Objectives: The primary aim of this study was to evaluate whether there is cortical auditory evoked potential (CAEP) evidence of impaired sensory gating in individuals with tinnitus. On the basis of the proposed mechanism of tinnitus generation, including a thalamocortical inhibitory deficit, it was hypothesized that individuals with tinnitus would lack the normal inhibitory effect on the second CAEP response in a paired-click sensory gating paradigm, resulting in larger sensory gating ratios in individuals with tinnitus relative to age-, sex-, and hearing-matched controls. Further, this study assessed the relative predictive influence of tinnitus presence versus other related individual characteristics (hearing loss, age, noise exposure history, and speech perception in noise) on sensory gating.

Onset-offset cortical auditory evoked potential amplitude differences indicate auditory cortical hyperactivity and reduced inhibition in people with tinnitus.

Objective: The current study investigates evidence of hypothesized reduced central inhibition and/or increased excitation in individuals with tinnitus by evaluating cortical auditory onset versus offset responses.

Methods: Cortical auditory evoked potentials (CAEPs) were recorded to the onset and offset of 3-second white noise stimuli in tinnitus and control groups matched in pairs by age, hearing, and sex (n = 26 total). Independent t-tests and 2-way mixed model ANOVA were used to evaluate onset-offset differences in amplitude, area, and latency of CAEP components by group.

Informational Masking Effects of Speech Versus Nonspeech Noise on Cortical Auditory Evoked Potentials.

Purpose Background noise has been categorized as energetic masking due to spectrotemporal overlap of the target and masker on the auditory periphery or informational masking due to cognitive-level interference from relevant content such as speech. The effects of masking on cortical and sensory auditory processing can be objectively studied with the cortical auditory evoked potential (CAEP). However, whether effects on neural response morphology are due to energetic spectrotemporal differences or informational content is not fully understood.

Informational Masking Effects of Similarity and Uncertainty on Early and Late Stages of Auditory Cortical Processing.

Purpose: Understanding speech in a background of other people talking is a difficult listening situation for hearing-impaired individuals, and even for those with normal hearing. Speech-on-speech masking is known to contribute to increased perceptual difficulty over nonspeech background noise because of informational masking provided over and above the effects of energetic masking. While informational masking research has identified factors of similarity and uncertainty between target and masker that contribute to reduced behavioral performance in speech background noise, critical gaps in knowledge including the underlying neural-perceptual processes remain.

Impaired auditory processing and neural representation of speech in noise among symptomatic post-concussion adults.

The purpose of the study was to examine auditory event-related potential (AERP) evidence of changes in earlier and later stages of auditory processing in individuals with long-term post-concussion problems compared to healthy controls, with a secondary aim of comparing AERPs by functional auditory behavioral outcomes. P1-N1-P2 complex and P300 components recorded to speech in quiet and background noise conditions were completed in individuals with ongoing post-concussion symptoms following mTBI and healthy controls. AERPs were also examined between sub-groups with normal or impaired auditory processing by behavioral tests.

Auditory and Cognitive Behavioral Performance Deficits and Symptom Reporting in Postconcussion Syndrome Following Mild Traumatic Brain Injury.

Purpose This study examined auditory deficits and symptom reporting in individuals with long-term postconcussion symptoms following a single mild traumatic brain injury (mTBI) compared to age- and gender-matched controls without a history of mTBI. Method Case history interviews, symptom questionnaires, and a battery of central auditory and neuropsychological tests were administered to 2 groups. The mTBI group was a civilian population recruited from a local concussion management program who were seeking rehabilitation for postconcussion-related problems in a postacute period between 3 and 18 months following injury.

Comparison of Silent Gap in Noise Cortical Auditory Evoked Potentials in Matched Tinnitus and No-Tinnitus Control Subjects.

Purpose Previous research suggests the existence of gap detection impairments because of tinnitus. The current study aimed to determine whether there was objective evidence of gap impairment in individuals with tinnitus by recording silent gap in white noise cortical auditory evoked potentials (CAEPs) in a chronic tinnitus group and a no-tinnitus group. The results were compared to previous gap-evoked potential and behavioral gap detection studies.

Informational Masking Effects on Neural Encoding of Stimulus Onset and Acoustic Change.

Objective: Recent investigations using cortical auditory evoked potentials have shown masker-dependent effects on sensory cortical processing of speech information. Background noise maskers consisting of other people talking are particularly difficult for speech recognition. Behavioral studies have related this to perceptual masking, or informational masking, beyond just the overlap of the masker and target at the auditory periphery.

Hearing Loss and Age-Induced Changes in the Central Auditory System Measured by the P3 Response to Small Changes in Frequency.

Background: Recent behavioral studies have suggested that individuals with sloping audiograms exhibit localized improvements in frequency discrimination in the frequency region near the drop in hearing. Auditory-evoked potentials may provide evidence of such cortical plasticity and reorganization of frequency maps.

Purpose: The objective of this study was to evaluate electrophysiological evidence of cortical plasticity related to cortical frequency representation and discrimination abilities in older individuals with high-frequency sensorineural hearing loss (SNHL).

Brainstem Evoked Potential Indices of Subcortical Auditory Processing After Mild Traumatic Brain Injury.

Objectives: The primary aim of this study was to assess subcortical auditory processing in individuals with chronic symptoms after mild traumatic brain injury (mTBI) by measuring auditory brainstem responses (ABRs) to standard click and complex speech stimuli. Consistent with reports in the literature of auditory problems after mTBI (despite normal-hearing thresholds), it was hypothesized that individuals with mTBI would have evidence of impaired neural encoding in the auditory brainstem compared to noninjured controls, as evidenced by delayed latencies and reduced amplitudes of ABR components. We further hypothesized that the speech-evoked ABR would be more sensitive than the click-evoked ABR to group differences because of its complex nature, particularly when recorded in a background noise condition.

Erratum: The Application of the International Classification of Functioning, Disability and Health to Functional Auditory Consequences of Mild Traumatic Brain Injury.

[This corrects the article DOI: 10.1055/s-0036-1584409.].

Identification of conductive hearing loss in young infants using tympanometry and wideband reflectance.

Objective: The goal of the study was to evaluate the effectiveness of tympanometry and wideband reflectance (WBR) in detecting conductive hearing loss (CHL) in young infants.

Methods: Type of hearing loss was determined using auditory brainstem response using air- and bone-conducted tone bursts in 84 ears from 70 infants (median age = 10 weeks). Of these 84 ears, 60 are included in the current analysis: 43 with normal hearing (NH) and 17 with CHL.

Brain stem responses to speech in younger and older adults.

Objective: This experiment was designed to evaluate whether neural encoding of speech features at the brain stem level is altered in the aging auditory system. In addition, the effect of minimal peripheral hearing loss on the auditory brain stem response (ABR) evoked by speech stimuli and interactions with aging were examined.

Design: Speech-evoked ABRs (S-ABRs) were recorded using a synthetic 40-msec /da/ stimulus from both ears of participants in two groups: normal-hearing younger adults (n = 19) and normal-hearing older adults (n = 18).

Accuracy and time efficiency of two ASSR analysis methods using clinical test protocols.

Background: The number of commercially available evoked potential systems implementing multiple-frequency auditory steady-state response (ASSR) techniques has increased over the last several years. The majority of data in the multiple-frequency ASSR literature have been obtained using time-domain averaging and Fast Fourier Transform (FFT) techniques with F-test statistical analysis. Another commercially available analysis method has been introduced using an adaptive filtering algorithm called the Fourier Linear Combiner (FLC).

Infant air and bone conduction tone burst auditory brain stem responses for classification of hearing loss and the relationship to behavioral thresholds.

Objective: A clinical protocol for diagnosing hearing loss (HL) in infants designed to meet early intervention guidelines was used with the goals of providing normative data for (1) frequency-specific tone burst auditory brain stem response (TBABR) thresholds by air conduction (AC) and bone conduction (BC) in early infancy used to classify type and severity of HL, (2) ear-specific behavioral thresholds for these same infants by 1 yr of age, and (3) the relationship between TBABR thresholds and behavioral thresholds for this group of infants.

Design: AC- and BC-TBABRs were measured in young infants (mean age, <3 mo) under natural sleep to classify the type and severity of HL (conductive, sensorineural, or mixed). A small group of normal-hearing adults undergoing the same TBABR protocol served as a control group.

Test-retest reliability of wideband reflectance measures in infants under screening and diagnostic test conditions.

Objective: The main goal of this study was to examine the test-retest reliability of wideband reflectance (WBR) measures collected from infants in screening and diagnostic hearing test environments. In addition, the results of WBR testing for infants who passed and failed otoacoustic emission (OAE) screening were examined to determine whether these measures distinguished between the two groups.

Design: Repeated WBR measures were collected from two groups of infants, one group tested in an outpatient hearing screening setting and the other group in a diagnostic test setting.

Effect of audiometric configuration on threshold and suprathreshold auditory steady-state responses.

Objective: The purpose of this study was to examine the correlation between auditory steady-state response (ASSR) thresholds and behavioral thresholds in hearing-impaired adults with two common audiometric configurations. A second goal was to compare suprathreshold ASSR growth functions in these two subject groups and to determine whether these growth functions could be used clinically to improve threshold estimation.

Design: Thirty adults participated, including 10 subjects with normal hearing, 10 subjects with flat moderately severe sensorineural hearing loss, and 10 subjects with sloping high-frequency sensorineural hearing loss.

Estimating air-bone gaps using auditory steady-state responses.

Auditory steady-state responses (ASSR) were recorded using stimuli presented both via air conduction (AC ASSR) and bone conduction (BC ASSR) in 10 normal-hearing subjects with different degrees of simulated conductive hearing losses. The ASSR-estimated ABG (air-bone gap) was compared with the ABG measured using traditional pure-tone audiometric procedures. Reproducibility of the BC ASSR electrophysiological thresholds was also assessed.

Comparison of auditory steady-state response and auditory brainstem response thresholds in children.

Recently, auditory steady-state responses (ASSRs) have been proposed as an alternative to the auditory brainstem response (ABR) for threshold estimation. The goal of this study was to investigate the degree to which ASSR thresholds correlate with ABR thresholds for a group of sedated children with a range of hearing losses. Thirty-two children from the University of Iowa Hospitals and Clinics ranging in age from 2 months to 3 years and presenting with a range of ABR thresholds participated.